Pollutants Degradation Characteristics and Microbial Community Structure Using Cornstarch Wastewater as Denitrification Carbon Source

Using cornstarch wastewater as carbon source for denitrification, the removal effects of nitrate nitrogen and organic matter were studied. The degradation characteristics of dissolved organic matter were investigated by excitation-emission matrix spectrum(EEMs) combined with parallel factor analysis(PARAFAC), and the community structure of microorganisms in activated sludge was analyzed by high-throughput sequencing. The results showed that the removal rate of NO_x^--N(the total concentrations of NO₃^--N and NO ₂^--N) was 96.80%. Two kinds of fluorescence components can be identified by EEMs-PARAFAC, including tyrosine-like substance Component 1(230 nm/310 nm, 275 nm/310 nm) and tryptophan-like substance Component 2(220 nm/350 nm, 280 nm/350 nm). The fluorescence intensity of Component 1 showed a downtrend and disappeared finally, which illustrated that the substance could be completely degraded by microorganisms. The fluorescence intensity of Component 2 gradually increased and Component 2 was the byproduct of microbial metabolism. Three dominant bacteria in the acclimated sludge were uncultured bacterium, Burkholderiales and Rhodocyclales, and the relative abundance of them was 18.54%, 14.65% and 14.13%, respectively.